---
name: "socketpair"
section: "2freebsd"
platform: "linux"
package: "freebsd-manpages"
version: "12.2-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/socketpair/2freebsd"
---

# socketpair(2freebsd)

create a pair of connected sockets

## NAME

**socketpair** – create a pair of connected sockets

## LIBRARY

Standard C Library (libc, -lc)

## SYNOPSIS

**#include \<sys/types.h\>**

**#include \<sys/socket.h\>**

*int*\

**socketpair**(*int domain*, *int type*, *int protocol*, *int \*sv*);

## DESCRIPTION

The **socketpair**() system call creates an unnamed pair of connected sockets in the specified communications *domain*, of the specified *type*, and using the optionally specified *protocol*. The descriptors used in referencing the new sockets are returned in *sv*\[0\] and *sv*\[1\]. The two sockets are indistinguishable.

The SOCK\_CLOEXEC and SOCK\_NONBLOCK flags in the *type* argument apply to both descriptors.

## RETURN VALUES

The **socketpair()** function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

## ERRORS

The call succeeds unless:

- \[EMFILE\]

  Too many descriptors are in use by this process.

- \[EAFNOSUPPORT\]

  The specified address family is not supported on this machine.

- \[EPROTONOSUPPORT\]

  The specified protocol is not supported on this machine.

- \[EOPNOTSUPP\]

  The specified protocol does not support creation of socket pairs.

- \[EFAULT\]

  The address *sv* does not specify a valid part of the process address space.

## SEE ALSO

[pipe(2)](/pipe/2.md), [read(2)](/read/2.md), [socket(2)](/socket/2.md), [write(2)](/write/2.md)

## STANDARDS

The **socketpair**() system call conforms to IEEE Std 1003.1-2001 (“POSIX.1”) and IEEE Std 1003.1-2008 (“POSIX.1”).

## HISTORY

The **socketpair**() system call appeared in 4.2BSD.

## BUGS

This call is currently implemented only for the UNIX domain.